This responsive menu is a step on from the CSS3 Multi-Level, Off-Canvass Mobile Menu (no JavaScript) and provides both a mobile and desktop view of the menu. You just need to follow the steps carefully on the tutorial page and all will be done just in few seconds.

Though this technique may be well-suited to certain situations and menu structures, there are still a lot of other options out there for taming navigation on mobile devices.
I hope the above tutorial will help you a lot, in case you need further help please let me know. Thanks